What Makes WEB-INF

I saw a JSP servlet running on Oracle 9i. The Java classes are stored
in WEB-INF/classes, WEB-INF/lib, META-INF directories.

I tried to read through Oracle 9i documentation, but I don't find any
information regarding any application which will create such directory
and Java classes. I assume I may miss out some documents.

Can anyone points me to the documentation name, as well as the PDF filename?

Is there a Java program provided by Oracle to create such a structure?

If I would like to migrate thoese installed files + Java classes into
another server, without the installation file, is there any
documentation on how to setup the environment? Or, is there any
document on the things behind the publishing program do?